Transvesical Approach in Robot-Assisted Bladder Diverticulectomy: Surgical Technique and Outcome

Introduction

A bladder diverticulum is defined as a protrusion of the urothelial mucosa at a weak site of the muscular layers of the bladder. ¹ Bladder diverticula are either congenital or acquired. Congenital or primary bladder diverticula are usually present since childhood and occur in the absence of bladder outlet obstruction (BOO), whereas bladder diverticula in adults are mostly secondary to BOO. ² Indications for surgical treatment include recurrent urinary tract infections (UTIs), stones, tumors, ureteral obstruction, and symptomatic incomplete bladder emptying. ³

Several treatment modalities are available, including open surgery, endoscopic resection or fulguration, laparoscopic surgery, and, more recently, robot-assisted surgery. ⁴ In this context, robot-assisted bladder diverticulectomy (RABD) has become a valid option for the most complex cases, with optimal perioperative outcomes in recent small series. These RABD series were mostly based on resections performed using an extravesical approach. Therefore, limited evidence is available on RABD performed using a transvesical approach. We will present our technique and outcome using a transvesical approach for RABD.

Patients and Surgical Procedure

After obtaining IRB approval, we retrospectively analyzed the perioperative and postoperative outcomes of 23 patients treated between March 2015 and May 2020 by four experienced robotic surgeons at a single high-volume center (Onze-Lieve-Vrouwziekenhuis, Aalst, Belgium). The indications for surgery are listed in Table 1. Before surgery, a cystoscopy is performed to exclude malignancy in the diverticulum. The patient is placed in supine 25° to 35° degrees Trendelenburg position, allowing for side-docking of the robotic system (DaVinci Xi). Trocar placement closely replicate the trocar placement of a standard robot-assisted radical prostatectomy (i.e., midline camera trocar just above the umbilicus, a 5-mm trocar in the right hypogastric space for the suction device, and a 12-mm trocar in the right fossa). The instruments used are the following: 0° camera, monopolar curved scissors, fenestrated bipolar forceps, and a large needle driver.

For a complete visualization of the procedure, we refer to Supplementary Video S1. The bladder is filled up to 200 mL with saline through transurethral catheter. The overlying peritoneum and detrusor muscle are incised until the bladder lumen is entered. Stay sutures on the edges of the cystotomy can be used to improve exposure. The orifices and the diverticular neck are identified. The mucosa covering the neck of the diverticulum is incised, and the plane between the mucosa and muscularis is identified. Using traction and blunt dissection, the mucosa is separated from the surrounding structures. The base of the diverticulum is transected using monopolar cautery.

After excising the diverticulum, the remnant defect is closed with a running suture using V-Lock 3–0. If intended upfront, an outlet procedure (e.g., simple adenomectomy) or radical prostatectomy can be performed after the diverticulectomy. To avoid clot retention, all clots are removed using the suction device before closure of the cystotomy. After completing the procedure, the cystotomy is closed in two layers with running suture using V-lock 3-0. To finish the procedure, a leakage test is performed in view of early catheter removal.

Intraoperative (operative time, blood loss, and intraoperative complications) and perioperative outcomes (length of stay and urinary catheter removal) were assessed. Postoperative complications were collected based on patient chart review done by a dedicated data manager and medical doctors and were graded according to Clavien–Dindo classification (CDC) system. Postoperative complications were also classified as early or late if they happened before or after 90 days from the surgery. Follow-up consisted of control visit at 1, 3, 6 months, and then annually.

Results

Details of our patient cohort are outlined in Table 2. The median age was 66 years (interquartile range [IQR] 60–69), the number of diverticula removed ranged from 1 to 3 and the median maximal diameter was 7 cm (IQR 5.4–9.7). Ten patients were treated with RABD alone, 12 underwent a simultaneous simple prostatectomy and 1 patient was treated with a simultaneous radical prostatectomy. Perioperative and postoperative outcomes are summarized in Table 3. Median operative time for patients who were treated with RABD alone was 123 minutes (IQR 120–155), median estimated blood loss was 250 mL (IQR 28–438). No patient required transfusion or conversion to open surgery. Median catheterization time and hospitalization time were 2 days (IQR 1–5) and 3 days (IQR 2–4), respectively.

One patient experienced low abdominal pain after catheter removal, which was suspicious for urinary leakage, and was treated with insertion of a transurethral catheter for additional 5 days (with complete symptom resolution after catheter removal). One patient developed a UTI. No other early postoperative complications were recorded. Median follow-up was 9 months (IQR 3–14), which consisted of uroflowmetry and sonographic evaluation of the bladder. No late postoperative complications were recorded. None of the patients experienced diverticulum relapse. Average postvoid residual (PVR) at last follow-up was 42 mL (IQR 0–111) with a median decline of 120 mL (IQR −402 to −33).

Discussion

In recent years more authors started reporting on the use of the robotic system for the treatment of bladder diverticula. To our knowledge, this is the largest series in RABD using a transvesical approach. The main advantages of this technique are the quick identification of the diverticular neck, and its relationship with the orifices. In 2012, a review was performed identifying 13 retrospective studies investigating RABD, including a total of 44 patients. ⁴ In those 13 studies, 12 described an extravesical approach, and only used a transvesical approach in a single patient.

After this review, six more articles were published reporting on RABD in the adult population with a total of 55 patients. ^{5 –10} Davidiuk et al. described a traditional extravesical approach as well as a modified internal dissection technique, going immediately into the diverticulum. ⁶ This latter technique was significantly shorter, with the former technique clearly avoiding issues with the observation of the ureter. ⁶ De Castro Abreu and colleagues described a transvesical approach in the majority of their patients, although their transvesical approach is mainly used to identify the diverticular neck, whereas the dissection itself is performed from outside the bladder. ⁵ Liu and coworkers report their experience in 20 procedures, of which 11 were performed using a comparable transvesical approach. ¹⁰

Mean operative time for patients treated with a diverticulectomy alone was 137 minutes, which is comparable with our series. Average estimated blood loss, hospital stay, and complication rate were also comparable: 100 mL, 2 days, and one Clavien grade ≥3 complication, respectively. Mean time to catheter removal, however, was 12 days, whereas we report a short median catheterization time of 2 days. In our experience, when closing the diverticular defect and the cystotomy with a barbed suture using a running suture, a watertight closure can be achieved. Moreover, performing a leakage test can help in the decision for early catheter removal. Concerning functional results, subjective improvement of voiding function measured using a variety of symptom scores after RABD has already been described. ^5,6,10 We observed a significant decrease in PVR with a median decline of 120 mL. No relapse has been reported, confirming the efficacy of this technique.

Although we did not perform a comparative analysis with an extravesical approach, our results support the feasibility, safety, and reliability of the transvesical approach for this particular surgical procedure. We believe that this technique aids in quick identification of the diverticulum and of the ureteral orifices, thus safeguarding the ureters. When confident about suturing the diverticular defect and cystotomy, a short catheterization time is feasible. Finally, this approach provides the advantage of performing a simultaneous adenomectomy or stone removal when necessary. In summary, excellent peri- and postoperative outcomes have been achieved.

Conclusion

Our transvesical approach in the robot-assisted resection of bladder diverticula is a safe and reliable technique, which gives the advantage of a quick localization of the diverticulum and orifices. It provides the surgeon with a direct access to the prostate when simultaneous desobstruction is necessary. Catheterization time is short and no relapse has been observed.